Sec Form 4 Filing - MOSLEY WILLIAM D @ Seagate Technology plc - 2020-07-28

FORM 4 Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934, Section 17(a) of the Public Utility Holding Company Act of 1935 or Section 30(h) of the Investment Company Act of 1940

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1. Name and Address of Reporting Person MOSLEY WILLIAM D 2. Issuer Name and Ticker or Trading Symbol Seagate Technology plc [ STX] 5. Relationship of Reporting Person(s) to Issuer (Check all applicable) X __ Director _____ 10% Owner X __ Officer (give title below) _____ Other (specify below) Chief Executive Officer (Last) (First) (Middle) SEAGATE TECHNOLOGY PLC, 47488 KATO ROAD 3. Date of Earliest Transaction (MM/DD/YY) 07/28/2020 (Street) FREMONT, CA94538 4. If Amendment, Date Original Filed (MM/DD/YY) 6. Individual or Joint/Group Filing (Check Applicable Line) __ X __ Form filed by One Reporting Person _____ Form filed by More than One Reporting Person (City) (State) (Zip)

Table I - Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned 1.Title of Security (Instr. 3) 2. Transaction Date (MM/DD/YY) 2A. Deemed Execution Date, if any (MM/DD/YY) 3. Transaction Code (Instr. 8) 4. Securities Acquired (A) or Disposed of (D) (Instr. 3, 4 and 5) 5. Amount of Securities Beneficially Owned Following Reported Transaction(s) (Instr. 3 and 4) 6. Ownership Form: Direct (D) or Indirect (I) (Instr. 4) 7. Nature of Indirect Beneficial Ownership (Instr. 4) Code V Amount (A) or (D) Price Ordinary Shares 07/28/2020 A 13,300 ( 1 ) A $ 0 348,590 ( 2 ) D Ordinary Shares 07/28/2020 A 16,842 ( 3 ) A $ 0 365,432 D Ordinary Shares 07/28/2020 A 12,677 ( 4 ) A $ 0 378,109 D Ordinary Shares 07/28/2020 A 13,007 ( 5 ) A $ 0 391,116 D

Table II - Derivative Securities Acquired, Disposed of, or Beneficially Owned ( e.g. , puts, calls, warrants, options, convertible securities) 1. Title of Derivative Security (Instr. 3) 2. Conversion or Exercise Price of Derivative Security 3. Transaction Date (MM/DD/YY) 3A. Deemed Execution Date, if any (MM/DD/YY) 4. Transaction Code (Instr. 8) 5. Number of Derivative Securities Acquired (A) or Disposed of (D) (Instr. 3, 4, and 5) 6. Date Exercisable and Expiration Date (MM/DD/YY) 7. Title and Amount of Underlying Securities (Instr. 3 and 4) 8. Price of Derivative Security (Instr. 5) 9. Number of Derivative Securities Beneficially Owned Following Reported Transaction(s) (Instr. 4) 10. Ownership Form of Derivative Security: Direct (D) or Indirect (I) (Instr. 4) 11. Nature of Indirect Beneficial Ownership (Instr. 4) Code V (A) (D) Date Exercisable Expiration Date Title Amount or Number of Shares

Reporting Owners Reporting Owner Name / Address Relationships Director 10% Owner Officer Other MOSLEY WILLIAM D SEAGATE TECHNOLOGY PLC 47488 KATO ROAD FREMONT, CA94538 X Chief Executive Officer Signatures /s/ Leanne M. Mader Attorney-in-Fact for William D. Mosley 07/29/2020 Signature of Reporting Person Date

Explanation of Responses:

( 1 )On July 28, 2020, the Compensation Committee of the Board of Directors of the Issuer determined that the performance conditions were met with respect to 13,300 of the 53,201 Threshold Performance Share Units granted to Mr. Mosley on September 9, 2016. The 13,300 Ordinary Shares will vest on September 9, 2020, subject to continuous service through such date. ( 2 )Includes 516 Ordinary Shares purchased by Reporting Person on January 31, 2020 under the Issuer's Employee Stock Purchase Plan. Such acquisition is exempt from reporting pursuant to Rule 16b-3 under the Securities Exchange Act of 1934. ( 3 )On July 28, 2020, the Compensation Committee of the Board of Directors of the Issuer determined that the performance conditions were met with respect to 16,842 of the 67,367 Threshold Performance Share Units granted to Mr. Mosley on September 11, 2017. The 16,842 Ordinary Shares will vest on September 11, 2020, subject to continuous service through such date. ( 4 )On July 28, 2020, the Compensation Committee of the Board of Directors of the Issuer determined that the performance conditions were met with respect to 12,677 of the 50,706 Threshold Performance Share Units granted to Mr. Mosley on September 10, 2018. The 12,677 Ordinary Shares will vest on September 10, 2020, subject to continuous service through such date. ( 5 )On July 28, 2020, the Compensation Committee of the Board of Directors of the Issuer determined that the performance conditions were met with respect to 13,007 of the 52,027 Threshold Performance Share Units granted to Mr. Mosley on September 9, 2019. The 13,007 Ordinary Shares will vest on September 9, 2020, subject to continuous service through such date.

Remarks: Exhibit 24 - Power of Attorney attached hereto.

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